Traffic controlling system for railroads



April 19, 1932.

A. LANGDON TRAFFIC CONTROLLING SYSTEM FOR RAILROADS 2 Sheets-Sheei Filed Jan,

INVENTOR W BY i 4/. W ATTORNEY April 19,1932. A, LANGDON TRAFFIC CONTROLLING SYSTEM FORRAILROADS Filed Jan. 11. 1930 2 Sheets-Sheet M ATTORNEY Patented Apr. 19, 1932 UNETED STATES PATENT OFFICE ANDREW LANGDON, OF ROCHESTER, NEW YORK, ASSIGNOB TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK 'rRAFr'Io CONTROLLING SYSTEM son RAI'LnoADs Application filed January 11, 1930. Serial No. 420,225.

This invention relates to trafiiccontrolling systems for railroads, and more particularly pertains to devices and circuits for the control of electrical power operated switch machines in such systems.

Among the objects of this invention, is to provide the control of electrical power operated switch machines by what may be con veniently termed free levers, that is, by

control levers which may be moved to new positions by the operator at any time. A

further object is to provide that the switch machines may be operated in accordance with the positions of their respective control levers at any time that their associated detector track sections are unoccupied,and also that the switch machines shall complete their operations should the respective control levers be returned to former governing positions immediately after the occupancy of the respective detector tracksections but before the switch machines had completed the operations already initiated.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in-which like reference characters designate corresponding parts throughout the several views, and in which Fig. 1 is a diagrammatic representation of a trafiic controlling system embodying the present invention as applied to the control of a reversible switch machine having a snubbing circuit; .1

Fig. 2 is a modification of Fig. 1 showing in a diagrammatic manner the control of a reversible switch machine without a snubbing circuit.

' With reference to Fig. 1 of the accom-' panyingdrawings, a track switch TS is provided with a switch machine SM for operating it to either its normal or reverse extreme locked positions. TS connects a passing siding comprising rails 5 with a main track comprising'rails 6. Associated with the track switch TS is This track switch 7 the usual detector track section DT including a portion of the passing siding up to the fouling point. The detector track section DT is isolated from other tr'ack sections by the usual insulated joints and has its various individual rails inter-connected by the usual bonding wires in accordance with common practice. This track section DT includes a track relay T and a track battery 7 with the conditions of the track section, as indicated by the track relay T, repeated in the tower by a track repeating relay TR.

The switch machine SM is diagrammatically represented within a dotted rectangle shown as including an armature A, a field winding F, a group of pole changing contacts, two pairs of pole changer coils and a group of pole changer coil contacts. This switch machine SM may be of any suitable type, such for example, as shown in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923. The switch machine SM is connected to a track switch TS in the usual manner and operates as set forth in the above mentioned Patent No. 1,466,903.

In the tower, a control lever L is provided which operates movable contact members 10 and 11 upon pivotedcentral points 13 and 14 respectively. The movable contact 11 is shown provided with a toggle spring ar rangement which causes the contact 11 to as sume either of two extreme postions in a snap action movement when the lever L is moved to either of two corresponding positions. The movable contact 10 follows the movement of the movable contact 11 due to a connecting rod 12. The movable contacts 10 and 11 make contactbetween certain respective pairs of fixed contacts when in normal positions, as shown, and make contact between certain other respective pairs of fixed contacts when in reverse positions prefer ably assumed at approximately a ninety degree angle with the present normal positions.

A selector S of the mechanical stick type is provided with normal and reverse operating coils 15 and 16 which operate the contacts of the selector to either normal positions or re-' verse positions respectively.

A resistance 18 is provided in the snubbing circuit of the switch machine in case the switch machine SM is located relatively close to the tower.

It will be noted, that throughout the description of the embodiments of the present invention, the opposite terminals of all sources of electrical potential will be designated as 13+ and B, which sources may be the same sources of supply or other suitable sources all in accordance with the practical application of the invention. It is to be understood that these sources of electrical potential are preferably local to the points in- 15 dicated, also that they may be either direct current or alternating current according to the circumstances to be met in practice.

The track switch TS is shown in its normal position with the control lever L in a correjsponding position as indicated by the arrow The track repeating relay TB is energized, as the detector track section DT is unoccupied.

Let us assume that the operator desires to zshcontrol the track switch TS to a reverse locked position which is accomplished by the movement of the control lever L to the reverse position indicated by the arrow B. When the control lever L is moved to the reso verse postion, the normal snubbing circuit is opened and the reverse snubbing circuit is partially completed. Also, the initial reverse operating circuit is closed through the high resistance winding 16 of the selector S,

which winding prevents the flow of sufficient current to operate the switch machine. The current which flows in this initial circuit is sufficient, however, to cause the selector S to operate its contacts to reverse positions, in

* which the high resistance winding 16 is shunted out allowing suitable current to flow to operate the switch machine SM.

The initial reverse operating circuit for the switch machine SM, as completed upon the movement of the lever L to its reverse position, is traced as follows :-from the positive terminal of a suitable source of electrical potential indicated as 13+, through. fixed contact 20, movable contact 10 in its reverse position, fixed contact 2l,wires 22 and 23, front contact 24 of relay TR, wire 25, reverse winding 16 of selector S, wires 26 and 27, contacts 2829, wires30 and 31, armature A, wires 32 and 33, contacts 3 l35, wires 36 and 37, field winding F, wires 38 and 39, to the negative terminal of the suitable source indicated as B. The current'fiowing through this circuit is of insufficient value to operate the switch machine, but causes the contacts 40 and 41 of selector S to assume reverse dotted line positions. As soon as the contact l0 of selector S reaches its reverse position, the reverse coil 16 of selector .S is shunted out causing the'switch machine SM to operate with current flowing through a low resistance circuit from wire 22, through wire a5, reverse contact 40 of selector S, to the reverse operating wire 27 of the switch machine SM.

The switch machine SM now operates to unlock the track switch T S and causes it to be operated to its reverse locked position in the usual welllcnown manner. During the operation of the'track switch TS and at all such times that it is unlocked, movable contacts A6 and 47 are caused to assume intermediate positions completing circuits in such a manner that either the normal or the reverse pole changer coils 48 or 4-9 respectively are energized in accordance with whether the normal or reverse operation of the switch machine SM is in the process of completion. If the opposite control wire of the switch machine is energized during its operation, the opposite pair of pole changer coils is energized causing the movable contacts 29 and 35 to be operated to opposite positions in midstroke of the switch machine, which results in the operation of the switch machine to its former position, all of which is explained in the above mentioned Patent No. 1,466,903.

When the switch machine SM has operated the track switch TS to its reverse locked position, the movable contacts 29 and 35 are mechanically operated to opposite extreme reverse positions which opens the reverse operating circuit of the switch machine at contacts 28 29 and contacts 3l35 and closes the reverse snubbing circuit of the switch machine. This reverse snubbing circuit of the switch machine serves to dynamically brake the switch machine armature A and causes it to come to rest immediately. Also, the contacts 46 and 47 are mechanically operated from intermediate positions to extreme reverse positions.

The reverse snubbing circuit of the switch machine SM is traced as follows :from the upper terminal of the armature A, through wires 32 and 50, contacts 2951, wires 52 and 53, contact ll of selector S in its reverse position, wires 54 and 55, fixed contact 56, movable contact 11 in its reverse position,

fixed contact 57 wires 58 and 59, resistance 18, wires 60, 39 and 38, field winding F, wire 37, contacts 3561, wires 62 and 31, to the lower terminal of the armature A.

It will be noted, that should the detector track section DT become occupied shortly I after the control lever L was moved to the reverse position, the track repeating relay to its reverse position, but is prevented from returning to its former position, if the lever L is returned to its former position indicated by the arrow N. Also, the reverse operating wire 27 of the switch machine is still supplied with operating energy alof the selector S in reverse positions, the

lack of correspondence being due to the deenergization of the track repeating relay TR, the reverse operating circuit for the switch machine SM is traced as follows':from the positive terminal of a suitable source of electrical potential indicated as B+, through back contact 24 of relay TR, wires 23 and 45, reverse contact 40 of selector S, to the reverse operating wire 27 of the switch ma- 7 chine SM and through the reverse operating circuit already pointed out, to the negative terminal of the suitable source indicated as B-. This circuit causes the switch machine SM to complete its reverse operation during detector track circuit occupancy although the control lever L has been returned to its for mer position.

It is noted, that when control lever L is out of correspondence with the selector S during detector track circuit occupancy, the snubbing circuit of the switch machine SM then includes a back contact 69 of relay TR. This snubbing circuit of the switch machine SM is traced from normal operating or re- 3 verse indicating wire 52 through wire 53 to reverse contact 41 of selector S, wires 54 and 70, back contact 69 of relay TR, wires 71- and 72, fixed contact 73, movable contact 11 in its normal position, fixed contact 74, wlres 7 and 59, resistance 13, wire 60, to the common return wire 39 of the switch machine. The switch machine SM thus has a snubbing circuit regardless of whether the detector track section DT is occupied or not.

However, as soon as the detector track section DT is unoccupied, the front contact'63 of track repeater relay TB is closed which energizes the normal operating coil 15 of selector S (assuming lever L to be in its normal position) causing contacts 40 and 41 to assume normal positions thus energizing the normal operating wire 52 of the switch machine with operating energy causing it to return the track switch TS to its normal locked 1 position into correspondence with the lever L.

Assumlng that the switch machine SM is in its reverse position and that the control lever L is returned to its normal governing position indicated by the arrow-N, the initial normal operating circuit of the switch machine SM is traced as follows :from the positive terminal of a suitable source of electrical potential indicated as 13+, through fixed contact 64, movable contact in its normal position, fixed contact 65, wires 66 and 67, front contact 63, wire 76, normal operating coil 15 of selector S, wires 77 and 52, contacts 2951, wires 50 and 32, armature A. wires 31 and 62, contacts 35-61, wire 37, field winding F, wires 38 .and 39, to the negative terminal of the suitable source indicated as B-.. Contacts 40 and 41 of'the selector S are operated to normal positions, in which the normal operating coil 15 of the selector S is shunted out through a circuit from wire 66 through wire 78, normal contact 41 of selector S and wire 53, to the normal operating wire 52 of he switch machine SM.

The switch machine SM receives operating current through the low resistance normal operating circuit which causes it to unlock the track switch TS and operate it from its reverse position to a normal position and again lock it in the normal position. It is of course to be understood that the various conditions which are applicable to the system during the operation from a normal condition to a reverse condition as described above, are also applicable to the operation of the system from a reverse condition to a normal condition.

When the switch machine SM has locked the track switch in a normal extreme position, the normal snubbing circuit brings the armature A immediately to an at rest condition. This normal snubbing circuit, assuming no unusual conditions such as occupancy, of the detector track section DT, is traced as fol lows :from the upper terminal of armature A, through wires 32 and 33, contacts 34 35, wires 36 and 37, field winding F, wires 38, 39 and 60, resistance 18, wires 59 and 75, fixed contact 7 4, movable contact 11 in its normal position, fixed contact 73, wires 72 and 79, contact 40 of selector S in its normal position, reverse operating wire 27, contacts 28-29, wires 30 and 31', to the lower terminal of the armature A. V

l/Vith reference to Fig. 2 of the accompanying drawings, a traffic controlling system similar to Fig. 1 is shown in a diagrammatic manner accomplishing the control of a reversible switch machine which does not require a snubbing circuit. In describing the embodiment of the present invention as shown in Fig. 2, those devices which are similar to those in Fig. 1 will be designated by similar reference characters having the dis tinctive exponent a.

A control lever L is employed to operate the associated switch machine SM to normal or reverse positions when in corresponding positions indicated by the arrows N and B respectively. The switch machine SM operates the track switch TS having associated therewith a detector track section DT controlling the track repeater relay TR in the tower TR in a manner similar to that described for Fig. 1.

The switch machine SM is practically identical to switch machine SM shown in Fig. 1 with the exception that a brake BR is provided to replace the dynamic braking employed in Fig. 1. This brake BB is of the spring biased type, that is, it is normally biased to a braking condition by suitable spring actuating means, and is actively released by energization of its operating coil which is included in the operating circuit of the swltch machlne.

In other words, this brake BR is released at any such time that a current, of suflicient value to operate the switch machine, flows in the operating circuit of the switch machine including the brake BR. Other operating characteristics of the switch machine SM are identical to those pointed out for switch machine SM in Fig. 1.

Let us assume that the operator moves the control lever L from its normal position indicated by the arrow N to its reverse position indicated by the arrow R.

lVith the lever L in its reverse position, the initial reverse operating circuit of the switch machine SM is completed, which circuit is traced as follows :from the positive terminal of a suitable source of electrical potential indicated as 13+, through front contact 80 of relay TR, wires 81 and 82, reverse operating coil 83 of selector S, wires 84 and 85, fixed contact 86, movable contact 87 in its reverse position, fixed contact 88, wires 89 and 90, contacts 91-92, wires 93 and 94, armature A, wires 95 and 96, contacts 97 and 98, wires 99 and 100, field winding F, wire 101, winding of brake BR, wires 102 and 103, to the negative terminal of the suitable source indicated as B The current which flows in this circuit is of insufficient value to operate the switch machine SM or release its brake BR due to the high resistance of the reverse windind 83 of selector S. However, a current flows which is of sufficient value to cause the contacts of the selector S to be operated to reverse dotted line positions in which the posi tive terminal of a suitable source indicated as B+ is connected directly to the reverse operating wire of the switch machine SM through a circuit traced as follows :from the positive terminal of a suitable source of electrical potential indicated as 13+, through contact 104 of selector S in its reverse position, wires 105 and 85, fixed contact 86, movable contact 87 in its reverse position, fixed contact 88, wire 89, through reverse operat ing wire 90, through the reverse operating circuit of the switch machine as heretofore traced to the negative terminal of the suitable source indicated as B The current flowing in this circuit is sufficient to release the brake BR and cause the switch machine SMTto unlock the track switch TS and operate it to a reverse locked condition all in a manner as either heretofore pointed out for the operation of switch machine SM in Fig. 1 or as set forth in the above mentioned Patent No. 1,466,903.

It is deemed unnecessary to describe the manner in which the switch machine is reversible in midstroke as such operation will be obvious to those skilled in the art by comparison to Fig. 1. It is further obvious that as soon as the switch machine SM has locked the track switch TS in its reverse position and the movable contacts 92 and 98 are operated to reverse extreme positions, the armature A will be immediately brought to rest as the brake BB is then deenergized.

Should the detector track section DT become occupied at any time during the operation of the track switch TS, the switch machine SM will continue its operation in accordance with the position of the selector S regardless of the position of the control lever L after such detector track section occupancy. This is due to the fact, that deenergization of the track repeater relay TR applies positive potential directly to the control wires of the switch machine in accordance with the posiion of the selector S.

Assuming the switch machine SM to be operating the track switch TS to its reverse locked condition with the detector track section DT occupied and with the control lever L returned to its normal position after such de tector track section occupancy, the switch machine Sliil will continue its reverse operation due to its reverse operating circuit then established. This reverse operating circuit is traced as follows :from the positive terminal of a suitable source of electrical poten tial indicated as 13+, through back contact 80 of track repeater relay TR, wire 106, reverse contact 107 of selector S, wire 108, through the reverse control wire 90 and through the reverse operating circuit of the switch machine SM as heretofore traced to the negative terminal of the suitable source indicated as B-.

The operation of this modified form of the present invention from the reverse condition to the normal condition is merely an inverse function of the operation already described.

Thus, a traffic controlling system has been shown in two of its possible forms for accomplishing the control of track switches by electrical power operated switch machines employing control levers which may be operated to any position at any time by the operator regardless of trackway conditions, with the usual detector track circuit protection for switches. Also, the systems embodying the present invention provide the usual facilities in operation by accomplishing reversibility of the switch machines in midstrolre and by insuring the completion of an operation after detector track circuit occupancy regardless of the operations of the control levers subsequent thereto.

Having described two forms of a traffic controlling system as specific embodiments of the present invention, it is desired to be understood that these forms are selected to facilitate in the disclosure of the invention rather than to limit the number of forms which it my assume; and, it is to be further understood that various modifications, adaptations and alterations may be applied to the specific forms shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention except as limited by the appended claims.

Having described my invention, I now claim 1. In a traffic controlling system for railroads, a switch machine, a control lever governing the operation of said switch machine, a detector track circuit, a two position selector normally governed by said detector track circuit and said control lever for initial ly controlling the operating current of said switch machine, said control lever thereafter controlling said operating current, and means governed by said track circuit for applying said operating current to said switch machine in accordance with said two position selector and independently of the position of said control lever and effective only during the occupancy of said detector track circuit.

2. In a trafiic controlling system for railroads, a switch machine, a control lever, a detector track circuit, a selector having high resistance coils that limit the operating current of said switch machine below an operating value, means operated by said selector for shunting said coils in accordance with said lever when said detector track circuit is unoccupied, and other means governed by said detector track circuit for supplying operating current to said switch machine in accordance with said selector independently of said lever.

3. In a traffic controlling system for railroads, a switch machine having normal and reverse operating circuits, a detector track circuit associated with said switch machine, a control lever for initially closing said normal and reverse operating circuits, a two position selector having two high resistance windings included respectively in said initial normal and reverse operating circuits to thereby limit the current flow therein below an operating value, means operated by said selector to shunt the corresponding one of said windings that is in the initially closed operating circuit to thereby initially allow effective operating current to flow, said control lever thereafter having control of said eifective operating current except when said detector track circuit is occupied, and means causing said eifective operating current to flow regardless of the'position of said control lever and in accordance with said two position selected only during detector track circuit occupancy.

4:. In a trafi ic controlling system for railroads, the combination with a switch machine, its control lever, and a selector having high resistance coils, of a detector track circuit, and a back contact on the track relay of said detector track circuit for applying operating current to said switch machine during detector track circuit occupancy through contacts of said selector and ind pendentl f said control lever for completing an operation initiated before such detector track circuit occupancy.

5. In a traflic controlling system for railroads, a detector track circuit, a switch machine having normal and reverse operating circuits, a selector having two high resistance coils in series with said normal and reverse operating circuits respectively and limiting the current flow therein below the value required to operate said switch machine, a control lever having contacts for establishingsaid normal and reverse operating circuits, contact means operated by said selector upon energization of either of said coils for establishing a low resistance path shunting the corresponding coil, thereby causing said switch machine to be operated, and means operated by said detector track circuit for rendering said selector unresponsive to the position of said control lever and for establishing an alternative circuit for said switch machine while said, detector track circuit is occupied.

6. In a traffic controlling system for railroads, a detector track circuit, a switch machine having normal and reverse operating circuits, a selector having two high resistance coils in series with said normal and reverse operating circuits respectively and limiting the current flow therein below the value required to operate said switch machine, a control lever having contacts for initially estab lish-ing said normal and reverse operating circuits, contact means operated by said selector upon energization of either of said coils for establishing a low resistance path shunting the corresponding coil thereby causing said switch machine to be operated, a snubbing circuit completed when said selector is in correspondence with said lever, means governed by said detector track circuit for completing said snubbing circuit if said lever is out. of correspondence with said selector when said detector tracl: section is occupied, means causing said selector to be unresponsive to said control lever when said detector track circuit is occupied, and means causing said switch machine to complete any operation initiated before occupancy of said detector track circuit independently of the position of said control lever.

7 In a traffic controlling system for railroads, a detector track circuit, a switch machine having normal and reverse operating circuits, a selector having two high resistance windings in series with said normal and reverse operating circuits respectively and limiting the current flow therein below the value required to operate said switch machine, a control lever having contacts for initially establishing said normal and reverse operating circuits, contact means operated by said selector upon energization of either of said windings for establishing a low resistance path shunting the corresponding coil, thereby causing said switch machine to be operated, a snubbing circuit completed when said selector is in correspondence with said lever, means causing said selector to be unresponsive to said control lever when said detector track circuit is occupied, and means causing said switch machine to complete any operation initiated before occupancy of said detector track circuit independently of the position of said control lever.

8. In a trafiic controlling system for railroads, an electrically operated switch machine, a brake for said switch machine effective only when said switch machine is deenergized, a control lever, a detector track circuit, a selector having high resistance coils that limit the operating current of said switch machine below an operating value, means operated by said selector for shunting said coils in accordance with said lever when said detector track circuit is unoccupied, and other means governed by said detector track circuit for supplying operating current to said switch machine in accordance with said selector independently of said lever.

9. Control apparatus for controlling the operation of a track switch for railroads comprising, a switch machine for operating said track switch, a detector track circuit associated with said track switch, a normal and a reverse circuit for said switch machine each of which is broken when said switch machine assumes the corresponding position, a lever for closing said normal and said reverse circuit one at a time, and auxiliary means for establishing a corresponding auxiliary normal or reverse circuit entirely independent of said lever if said detector track circuit becomes occupied at any time after movement of said lever and before said switch machine has completed operation of an initiated stroke.

In testimony whereof I affix my signature.

ANDREW LANGD ON. 

